Really? They are usually not picky at all! In fact, some people have trouble getting rid of them!

Perhaps it is the lack of moisture that is making them poorly.

I got some bulbs last fall and planted them in woodsy soil under deciduous trees and very tall pines in my backyard. Leaf and straw has been allowed to rot down here for 20 years or more. Most get partial sun They are doing better in some areas than others and I think the difference is competition from tree roots. The ones in a bed in front of Azaleas under a pine are doing well. The ones farther back under a maple are not doing as well. Maple roots are usually bad. I also do think they like more water than they are getting. So I'm interested in answers that you get.

when do arum bulbs first start to grow anyway? I planted some last fall and now, in May, absolutely nothing is happening. does this mean they are dead? or should I give them more time?

I have arum in four different places in my yard. The sunniest and driest place (I have them in a bed with rosemary and lavender) does the worst. The group that does the best is in partial shade and gets the most food and water (mixed in with lenten roses and ferns). The other two groups are under the eaves of the house, so it is drier and partial shade. These groups grow well but don't spread very fast.

I have arum that I got from a friend many years ago. They too are planted in awful red clay (I did not amend much then either) and they are thriving in spite of the poor soil. They are in a mostly shaded area under an ash tree (receives very little morning sun only) and mulched with bark and chopped leaves, but they do receive a fair bit of moisture as they are near where water runs off the house (no gutters). In that same area I have Lenten Rose and Columbine and Hosta.